/*
 * Copyright (c) 2020-2021 ARM Limited
 * All rights reserved.
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 2012 Mark D. Hill and David A. Wood
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 */

#include "mem/ruby/common/Consumer.hh"

namespace gem5
{

namespace ruby
{

Consumer::Consumer(ClockedObject *_em, Event::Priority ev_prio)
    : m_wakeup_event([this]{ processCurrentEvent(); },
                    "Consumer Event", false, ev_prio),
      em(_em)
{ }

void
Consumer::scheduleEvent(Cycles timeDelta)
{
    m_wakeup_ticks.insert(em->clockEdge(timeDelta));
    scheduleNextWakeup();
}

void
Consumer::scheduleEventAbsolute(Tick evt_time)
{
    m_wakeup_ticks.insert(
        divCeil(evt_time, em->clockPeriod()) * em->clockPeriod());
    scheduleNextWakeup();
}

void
Consumer::scheduleNextWakeup()
{
    // look for the next tick in the future to schedule
    auto it = m_wakeup_ticks.lower_bound(em->clockEdge());
    if (it != m_wakeup_ticks.end()) {
        Tick when = *it;
        assert(when >= em->clockEdge());
        if (m_wakeup_event.scheduled() && (when < m_wakeup_event.when()))
            em->reschedule(m_wakeup_event, when, true);
        else if (!m_wakeup_event.scheduled())
            em->schedule(m_wakeup_event, when);
    }
}

void
Consumer::processCurrentEvent()
{
    auto curr = m_wakeup_ticks.begin();
    assert(em->clockEdge() == *curr);

    // remove the current tick from the wakeup list, wake up, and then schedule
    // the next wakeup
    m_wakeup_ticks.erase(curr);
    wakeup();
    scheduleNextWakeup();
}

} // namespace ruby
} // namespace gem5